Ship project history: This pair
was ordered by Portugal in 1931 as Delfim and
Espadarte, but the same year the contract was terminated. In 1932
they were re-ordered by Italian Government for own Navy. The project was developed on the basis of
Squalo class. Single-hulled, with external bulges.Successful
design, differed by easy manoeuvrability both in surface, and in underwater position,
fast and well armed.

Modernizations: None.

Naval service:Otaria
was badly damaged by
DCs and gunfire of British destroyer
Wishart and scuttled by own crew as
unoperable 27/6/1941 W of Gibraltar.